Format: ORAL

Montserrat Vil1,2, Alejandro Trillo1, Pilar Castro3, Belinda Gallardo4, Sven Bacher

1 Estación Biológica de Doñana (EBD-CSIC), Sevilla, Spain 2 Department of Plant Biology and Ecology, Universidad de Sevilla, Sevilla, Spain 3 Departament of Live Sciences, University of Alcalá, Alcalá de Henares, Spain 4 Applied and Restoration Ecology Group, Pyrenean Institute of Ecology (IPE-CSIC), Zaragoza, Spain 5 Department of Biology, University of Fribourg, Fribourg, Switzerland

Despite that many invasive species threaten biodiversity and ecosystems, their effects are highly idiosyncratic and context dependent. We compiled a comprehensive database of 287 publications on 4622 field studies on the ecological impacts of 114 invasive alien plants in 30 European countries to analyse their direction and frequency. Impacts were categorized across levels of ecological organization, taxa and feeding mode. Furthermore, if the information was available, the impacts were also classified based on the feeding mode of the impacted species or communities. Forty-four percent of the studies found significant impacts with more significant decreases (26.8%) than increases (16.6%) on the impact response variables. Negative impacts (i.e. statistically significant decreases) were more frequent on species and communities than on ecosystem properties. The impacts on ecosystem properties were highly variable. The frequency of negative impacts to species and communities was higher on plants than on animals, but the frequency of finding positive impacts (i.e. statistically significant increases) was similar between taxa. Finally, the frequency of negative impacts was higher on primary producers, herbivores and parasites than on decomposers, pollinators and predators, while the frequency of positive impacts was generally similar among feeding modes. Our database provides the first information system on field studies of the ecological impacts of invasive plant species at the continental scale. This information can be of interest for academic, management and policy purposes.